(a) Field of the Invention
This invention relates to 6-(lower-alkyl)-5-(pyridinyl)-2(1H)-pyridinones, their use as cardiotonic agents, and their preparation.
(b) Description of the Prior Art
Lesher and Opalka (U.S. Pat. Nos. 4,004,012, issued Jan. 18, 1977, and 4,072,746, issued Feb. 7, 1978) show as cardiotonic agents 3-amino(or cyano)-5-(pyridinyl)-2(1H)-pyridinones and also 3-unsubstituted-5-(pyridinyl)-2(1H)-pyridinones, which were prepared by heating the corresponding 3-cyano compounds with aqueous sulfuric acid, first forming the 3-carboxylic acids, i.e., 1,2-dihydro-2-oxo-5-(pyridinyl)nicotinic acids, which are then decarboxylated. No cardiotonic activity is shown for said 1,2-dihydro-2-oxo-5-(pyridinyl)nicotinic acids. The disclosure of U.S. Pat. No. 4,072,746 also is shown in Lesher and Opalka U.S. Pat. Nos. 4,107,315, 4,137,233, 4,199,586 and 4,225,715.